[CrazyIvan]

It may be known as heliarc but helium cannot perform the shielding function around the arc since helium is lighter than air. In many processes, argon is the preferred gas or in a mix with other gasses.

Helium is used for some light gage stainless welding with
other gasses added. Because it is blown across the weld its
weight is not a large consideration. Personally, I use a
85/15% argon/CO2 for MIG and 100% argon for TIG. This is
pretty much all mild steel. I used to run a shop that made
custom motorcycle frames and these mixes worked out pretty
well. Weld gas mix is one of those topics,like politics,
that people will discuss passionately for hours!

[T-Bird45]

You are certainly right about weld gas mixes being like politics. The shop I worked in was primarily aluminum (100% argon in MIG/TIG) and stainless (100% argon TIG, 75/25 for MIG). I’d not previously heard of light gauge S/S being done with a helium mix but our application was mostly pipe and tube, 16ga. and heavier.